Medical Device Delivery Systems and Methods

ABSTRACT

A delivery system for deploying a medical device includes a first attachment member configured to selectively couple to and radially constrain a first end portion of the medical device. The delivery system also includes a second attachment member configured to selectively couple to and radially constrain a second end portion of the medical device. The first attachment member is configured to move relative to the second attachment member such that the first attachment member applies a first tensile force to the first end portion of a medical device in a first direction and the second attachment member applies a second tensile force to the second end portion of a medical device in a second direction substantially opposite from the first direction.

BACKGROUND

1. Field

Embodiments of the invention relate to systems and methods for loadingan implantable medical device onto a delivery device and, particularly,to systems and methods for loading a valve prosthesis onto a deliverycatheter.

2. Background

Patients suffering from valve regurgitation or stenotic calcification ofthe leaflets can be treated with a heart valve replacement procedure. Atraditional surgical valve replacement procedure requires a sternotomyand a cardiopulmonary bypass, which creates significant patient traumaand discomfort. Traditional surgical valve procedures can also requireextensive recuperation times and may result in life-threateningcomplications.

One alternative to a traditional surgical valve replacement procedure isdelivering the replacement heart valve prosthesis usingminimally-invasive techniques. For example, a heart valve prosthesis canbe percutaneously and transluminally delivered to an implantationlocation. In such methods, a heart valve prosthesis can be compressed orcrimped on a delivery catheter for insertion within a patient'svasculature; advanced to the implantation location; and re-expanded tobe deployed at the implantation location. For example, a catheter loadedwith a compressed heart valve prosthesis can be introduced through anopening in the femoral artery and advanced through the aorta to theheart. At the heart, the prosthesis can be re-expanded to be deployed atthe aortic valve annulus, for example.

BRIEF SUMMARY

In some embodiments, a delivery system for deploying a medical deviceincludes a first attachment member configured to selectively couple toand radially constrain a first end portion of the medical device, and asecond attachment member configured to selectively couple to andradially constrain a second end portion of the medical device oppositethe first end portion. The first attachment member can be configured tomove relative to the second attachment member such that the firstattachment member applies a first tensile force to the first end portionof a medical device in a first direction and the second attachmentmember applies a second tensile force to the second end portion of amedical device in a second direction substantially opposite from thefirst direction.

In some embodiments, a method of deploying a medical device includescoupling a first end portion of the medical device to a first attachmentmember of a delivery system. The method also includes coupling a secondend portion of the medical device to a second attachment member of thedelivery system. Further, the method includes moving the firstattachment member relative to the second attachment member to increase adistance between the first attachment member and the second attachmentmember. Moving the first attachment member relative to the secondattachment member causes the first attachment member to apply a firsttensile force to the first end portion of the medical device in a firstdirection and the second attachment member to apply a second tensileforce to the second end portion of the medical valve in a seconddirection substantially opposite from the first direction, whereby themedical device is compressed.

A system for replacing a native heart valve of a patient includes aprosthetic heart valve and a delivery system for deploying theprosthetic heart valve. The prosthetic heart valve includes a frame anda valve assembly coupled to the frame. The frame includes a first endportion, an intermediate portion, and a second end portion. The deliverysystem includes a first attachment member configured to selectivelycouple to and radially constrain a first end portion of the prostheticheart valve. The delivery system also includes a second attachmentmember configured to selectively couple to and radially constrain asecond end portion of the prosthetic heart valve. The first attachmentmember can be configured to move relative to the second attachmentmember such that the first attachment member applies a first tensileforce to the first end portion of the prosthetic heart valve in a firstdirection and the second attachment member applies a second tensileforce to the second end portion of the prosthetic heart valve in asecond direction substantially opposite from the first direction.

Further features and advantages of the embodiments, as well as thestructure and operation of various embodiments, are described in detailbelow with reference to the accompanying drawings. It is noted that theinvention is not limited to the specific embodiments described herein.Such embodiments are presented herein for illustrative purposes only.Additional embodiments will be apparent to persons skilled in therelevant art(s) based on the teachings contained herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, illustrate the embodiments and, together with thedescription, further serve to explain the principles of the embodimentsand to enable a person skilled in the relevant art(s) to make and usethe embodiments.

FIG. 1 illustrates a perspective view of a delivery system according toan embodiment.

FIG. 2 illustrates a side view of first and second attachment members ofa delivery system according to an embodiment.

FIG. 3 is a top view of a first attachment member according to anembodiment.

FIG. 4 is a distal view of the first attachment member of FIG. 3 takenfrom line A-A in FIG. 3.

FIG. 5 is a cross-sectional view of the first attachment member of FIGS.3 and 4 taken from line B-B in FIG. 3.

FIG. 6 is a perspective view of a medical device for use with a deliverysystem according to an embodiment.

FIG. 7 is a top view of a first attachment member coupled to a first endportion of a medical device at a loading step according to anembodiment.

FIG. 8 is a cross-sectional view of the first attachment member coupledto the first end portion of a medical device of FIG. 7 taken from lineA-A in FIG. 7.

FIG. 9 is a cross-sectional view of the first attachment member coupledto the first end portion of a medical device of FIGS. 7 and 8 taken fromline B-B in FIG. 7.

FIG. 10 is a top view of a first attachment member coupled to the firstend portion of a medical device at another loading step according to anembodiment.

FIG. 11 is a cross-sectional view of the first attachment member coupledto the first end portion of a medical device of FIG. 10 taken from lineA-A in FIG. 10.

FIG. 12 is a cross-sectional view of the first attachment member coupledto the first end portion of a medical device of FIGS. 10 and 11 takenfrom line B-B in FIG. 10.

FIG. 13 is a side view of a medical device at a deployment stepaccording to an embodiment.

FIG. 14 is a side view of the medical device of FIG. 13 and a deliverysystem at a deployment step according to an embodiment.

FIG. 15 is a side view of the medical device and the delivery system atanother deployment step according to an embodiment.

FIG. 16 is a side view of the medical device and the delivery system atanother deployment step according to an embodiment.

FIG. 17 is a side view of the medical device and the delivery system atanother deployment step according to an embodiment.

FIG. 18 is a side view of the medical device and the delivery system atanother deployment step according to an embodiment.

FIG. 19 is a side view of the delivery system at another deployment stepaccording to an embodiment.

FIG. 20 is a side view of the delivery system at another deployment stepaccording to an embodiment.

The features and advantages of the embodiments will become more apparentfrom the detailed description set forth below when taken in conjunctionwith the drawings, in which like reference characters identifycorresponding elements throughout. In the drawings, like referencenumbers generally indicate identical, functionally similar, and/orstructurally similar elements.

DETAILED DESCRIPTION

The embodiments described, and references in the specification to “oneembodiment,” “an embodiment,” “an example embodiment,” “someembodiments,” etc., indicate that the embodiments described may includea particular feature, structure, or characteristic, but every embodimentmay not necessarily include the particular feature, structure, orcharacteristic. Moreover, such phrases are not necessarily referring tothe same embodiment. Further, when a particular feature, structure, orcharacteristic is described in connection with an embodiment, it isunderstood that such feature, structure, or characteristic can be usedin connection with other embodiments whether or not explicitlydescribed.

FIG. 1 illustrates a perspective view of a delivery system 10 having alongitudinal axis LA according to an embodiment. Delivery system 10 canbe configured to deliver a medical device 12 to an implantation locationwithin a patient's body.

In some embodiments, medical device 12 is a valve prosthesis, a stent,or any other suitable collapsible medical device. For example, medicaldevice 12 can be a valve prosthesis as shown in FIG. 6. Referring toFIG. 6, medical device 12 is a valve prosthesis that comprises acollapsible and expandable frame 42 and a valve assembly 44 coupled tothe frame. Frame 42 comprises a first end portion 46, for example, anoutflow portion of valve prosthesis 12; an intermediate portion 48; anda second end portion 50, for example, an inflow end of valve prosthesis12. In some embodiments, first end portion 46 comprises one or morecoupling members 52. In some embodiments, second end portion 50comprises one or more coupling members 54. For example, coupling members52 and 54 can have a paddle shape, an eyelet shape, a T-shape, or anyother suitable shape for coupling medical device 12 to delivery system10. Medical device 12 can be self-expanding.

Referring back to FIG. 1, delivery system 10 comprises a firstattachment member 14, for example, a spindle, configured to selectivelycouple to medical device 12 such that relative axial movement betweenfirst attachment member 14 and medical device 12 at the point ofcoupling (for example, at first end portion 46) is substantiallyprevented. Delivery system 10 also comprises a second attachment member16, for example, a spindle, configured to selectively couple to medicaldevice 12 such that relative axial movement between second attachmentmember 16 and medical device 12 at the point of coupling (for example,at second end portion 46) is substantially prevented. As shown in FIG.1, second attachment member 16 is distal to first attachment member 14.

Delivery system 10 can be configured such that first attachment member14 is axially movable relative to second attachment member 16 so that anaxial distance 17 between attachment members 14 and 16 changes as firstattachment member 14 moves relative to second attachment member 16. Insome embodiments, delivery system 10 can be configured such that asfirst attachment member 14 moves relative to second attachment member 16to increase distance 17 between first and second attachment members 14and 16, first attachment member 14 applies a first tensile force tomedical device 12 in a first direction, for example, in a proximaldirection parallel to longitudinal axis LA, and second attachment member16 applies a second tensile force to medical device 12 in a seconddirection substantially opposite from the first direction, for example,a distal direction parallel to longitudinal axis LA. Applying the firstand second tensile forces compresses—reduces an outer dimension—at leasta portion or, in some embodiments, substantially all of medical device12. Such compression of medical device 12 facilities delivery of medicaldevice 12 through a patient's body lumens and cavities by decreasing theouter dimension of medical device 12.

In some embodiments, first attachment member 14 applies the firsttensile force directly to coupling members 52 of medical device 12. Insome embodiments, first attachment member 14 applies the first tensileforce directly to a radially intermediate surface—a surface between theouter surface and the inner surface—of coupling members 52. In someembodiments, first attachment member 14 applies the first tensile forcedirectly to an axially intermediate surface—a surface between the axialends—of medical device 12. In some embodiments, second attachment member16 applies the second tensile force directly to coupling members 54 ofmedical device 12. In some embodiments, second attachment member 14directly applies the second tensile force to a radially intermediatesurface—a surface between the outer surface and the inner surface—ofcoupling members 54. In some embodiments, second attachment member 16applies the second tensile force directly to an axially intermediatesurface—a surface between the axial ends—of medical device 12. In someembodiments, the first and second tensile forces are substantiallycoaxial. In some embodiments, the first and second tensile forces aresubstantially parallel to the longitudinal axis of the delivery system10.

In some embodiments, first and second attachment members 14 and 16 canbe spindles or any other suitable attachment structures.

In some embodiments, delivery system 10 comprises an outer shaft 15 thatencompasses an inner shaft 26. Inner shaft 26 is movable relative toouter shaft 15. In some embodiments, first attachment member 14 is fixedrelative to outer shaft 15—first attachment member 14 moves with outershaft 15. In some embodiments, first attachment member 14 is integralwith outer shaft 15. In some embodiments, first attachment member 14 isa discrete component from outer shaft 15. In some embodiments, secondattachment member 16 is fixed relative to inner shaft 26—secondattachment member 16 moves with inner shaft 26. In some embodiments,second attachment member 16 is integral with inner shaft 26. In someembodiments, second attachment member 16 is a discrete component coupledto a distal end of inner shaft 26.

In some embodiments, first attachment member 14 can be configured toselectively and radially constrain at least a portion of medical device12, for example, first end portion 46, once medical device 12 is coupledto first attachment member 14. In such embodiments, first attachmentmember 14 substantially and selectively prevents outward radiallyexpansion of first end portion 46 of medical device 12. In someembodiments, when first attachment member 14 and second attachmentmember 16 apply the first and second tensile forces to compress medicaldevice 12, first attachment member 14 and second attachment member 16can also radially restrain respective portions of medical device 12.

In some embodiments, second attachment member 16 can be configured toselectively and radially constrain at least a portion of medical device12, for example, second end portion 50, once medical device 12 iscoupled to second attachment member 16. In such embodiments, secondattachment member 16 substantially and selectively prevents outwardradially expansion of second end portion 50 of medical device 12.

In some embodiments, outward radially expansion of intermediate portion48 of medical device 12 is substantially and selective prevented by theapplication of the first and second tensile force by first attachmentmember 14 and second attachment member 16, respectively.

In some embodiments, delivery system 10 does not include a capsule,minimizing the outer dimension of the delivery system.

FIG. 2 illustrates a side view of outer shaft 15, first attachmentmember 14, inner shaft 26, and second attachment member 16 according toan embodiment. Inner shaft 26 is slidably received within outer shaft15. First attachment member 14 is fixedly coupled to a distal end ofouter shaft 15. Inner shaft 26 extends distally beyond first attachmentmember 14 and is fixedly coupled to a proximal end 30 of secondattachment member 16.

As shown in FIG. 2, first attachment member 14 comprises at least onecoupling portion 18 configured to selectively couple with a portion ofmedical device 12, for example, first end portion 46 of medical device12 (see FIG. 6). In some embodiments, as best seen in FIG. 3, which is atop view of first attachment member 14, coupling portion 18 comprises anouter surface of first attachment member 14 that defines one or moreslots 24 each configured to receive a respective coupling member ofmedical device 12, for example, coupling members 52 of first end portion46 of the medical device 12 (see FIG. 6). The shape of slots 24 closelycorresponds to the shape of the respective coupling member 52 of medicaldevice 12. For example, if coupling members 52 are T-shaped, slots 24are similarly T-shaped as shown in FIG. 3, or if coupling members 52 arepaddle-shaped, slots 24 are similarly paddle-shaped.

Referring to FIG. 4 and FIG. 5, a view from line A-A in FIG. 3 and across-sectional view from line B-B in FIG. 3, respectively, firstattachment member 14 defines a central lumen 36 for slidably receivinginner shaft 26. In some embodiments, the coupling portion's outersurface 18 and distal end 22 of first attachment member 14 collectivelydefine a cavity 40. Cavity 40 is in communication with slots 24. Cavity40 is sized to receive coupling members 52 of medical device 12 afterpassing through slots 24. Cavity 40 has an opening 41 that allowsmedical device 12 to axially extend toward second attachment member 16when coupling members 52 are received within cavity 40. Cavity 40 cancircumferentially surround first attachment member 14.

In some embodiments, distal end 22 defines a shoulder 38 that axiallybounds cavity 40. Shoulder 38 can be sized and shaped to preventcoupling members 52 within cavity 40 from axially exiting cavity 40through opening 41. In some embodiments, shoulder 38 of first attachmentmember 14 applies the first tensile force to medical device 12 as firstattachment member 14 moves relative to second attachment member 16 toincrease axial distance 17. In some embodiments, shoulder 38 is sizedand shaped to apply the first tensile force directly to a radiallyintermediate surface of coupling members 52 of medical device 12. Insome embodiments, shoulder 38 is sized and shaped to apply the firsttensile force directly to an axially intermediate surface of medicaldevice 12, for example, a distal surface of coupling members 52. Whencoupling members 52 of medical device 12 are within cavity 40, thecoupling portion's outer surface 18 circumferentially surrounds andconstrains a portion of medical device 12, for example, first portion46, to prevent outward radially expansion of medical device 12 inself-expanding embodiments.

In some embodiments, delivery system 10 can be configured such thatfirst attachment member 14, including outer surface 18, rotates relativeto medical device 12 when coupling members 52 are within cavity 40. Forexample, a user can manipulate a proximal end of delivery system 10 tocause first attachment member 14 to rotates, for example, by rotatingouter shaft 15. Rotation of first attachment member 14 allows a user toselectively and radially align or misalign coupling members 52 ofmedical device 12 with slots 24 defined by coupling portion's outersurface 18.

In some embodiments, second attachment member 16 is substantially amirror image of first attachment member 14 as shown in FIGS. 3-5 butconfigured to couple to second end portion 50 and includes substantiallythe same features of first attachment member 14 described above. Forexample, as shown in FIG. 2, second attachment member 16 comprises acoupling portion 28 configured to couple to a portion of medical device12, for example, a second end portion 50 of medical device 12. As shownin FIG. 2, coupling portion 28 comprises an outer surface that definesone or more slots 34 each configured to receive a respective couplingmember 54 (see FIG. 6). The shape of slots 34 corresponds to the shapeof the respective coupling members 54 of medical device 12. For example,if coupling members 54 are T-shaped, slots 34 are similarly T-shaped, orif coupling members 54 are paddle-shaped, slots 34 are similarlypaddle-shaped. Second attachment member 16 also comprises a distal end32. In some embodiments, distal end 32 forms the distal tip of deliverysystem 10 and can have an atraumatic shape.

FIGS. 7-12 illustrate coupling of a portion of medical device 12, forexample, first end portion 46, with first attachment member 14 accordingto an embodiment. In some embodiments, coupling of a portion of medicaldevice 12, for example, second end portion 50, with second attachmentmember 16 is a mirror image of FIGS. 7-12.

In FIGS. 7-9, coupling members 52 of medical device 12 are radiallyaligned with slots 24 defined by coupling portion's outer surface 18.First end portion 46 of medical device 12 comprising coupling members 52is then compressed to pass coupling members 52 through slots 24 and intocavity 40 (see FIGS. 8 and 9). Shoulder 38 of first attachment member 14prevents coupling members 52 of medical device 12 from axially exitingcavity 40 through opening 41. Shoulder 38 also applies the first tensileforce to medical device 12, for example, at coupling members 52, whenfirst attachment member 14 moves relative to second attachment member 16to increase axial distance 17.

In FIGS. 10-12, first attachment member 14 is rotated relative tomedical device 12 such that at least a portion of coupling members 52 isradially misaligned with slots 24. Accordingly, solid portions ofcoupling portion's outer surface 18 are radially aligned with at leastportions of coupling members 52 to radially constrain the coveredportion of medical device 12 and prevent outward radial expansion of atleast first end portion 46 of medical device 12.

Delivery system 10 facilities deployment of a medical device within apatient's body lumen or cavity. FIGS. 13-20 schematically illustrate amethod of deploying medical device 12 according to an embodiment. InFIG. 13, medical device 12 is inserted within an accessory tube 56 bycompressing medical device 12 to an intermediate compressed diameter.The inner dimension of accessory tube 56 is larger than the outerdimension of second attachment member 16 so that second attachmentmember 16 can pass through medical device 12 when inserted in accessorytube 56. Accessory tube 56 has an axial length such that first endportion 46 (including coupling members 52) of medical device 12 extendsfrom one end of accessory tube 56, and second end portion 50 (includingcoupling members 54) extends from the other end of accessory tube 56. Insome embodiments, medical device 12 is loaded within accessory tube 56outside the patient.

Second attachment member 16 of delivery system 10 is then passed throughthe lumen of medical device 12 loaded with accessory tube 56 until firstend portion 46 of medical device 12 is axially aligned with firstattachment member 14 and coupling members 52 are radially aligned withslots 24 of first attachment member 14 as shown in FIG. 7.

In FIG. 14, to couple first end portion 46 of medical device 12 to firstattachment member 14 of delivery system 10, accessory tube 56 is slidrelative to medical device 12 in a proximal direction toward firstattachment member 14 to compress first end portion 46 such that couplingmembers 52 pass through slots 24 of first attachment member 14 and intocavity 40. First attachment member 14 can be rotated relative to medicaldevice 12 such that at least a portion of coupling members 52 areradially misaligned with slots 24 to radially constrain the coveredportions of medical device 12 and prevent outward radial expansion ofmedical device 12 as shown in FIGS. 10-12.

To couple second end portion 50 of medical device 12 to secondattachment member 16 of the delivery system 10, accessory tube 56 canthen be slid relative to medical device 12 in a distal direction towardsecond attachment member 16 to compress second end portion 50 such thatcoupling members 54 pass through slots 34 of second attachment member 16and into the cavity (similar to cavity 40 of first attachment member 14)defined by second attachment member 16. Second attachment member 16 canbe rotated relative to medical device 12 such that at least a portion ofcoupling members 54 are radially misaligned with slots 34 to radiallyconstrain the covered portions of medical device 12 and prevent outwardradial expansion of medical device 12 similar to how first attachmentmember 14 radially constrains medical device 12 as illustrated in FIGS.10-12.

In FIG. 15, accessory tube 56 is removed, and in FIG. 16, firstattachment member 14 is moved relative to second attachment member 16 toincrease distance 17 between first attachment member 14 and secondattachment member 16. Increasing distance 17 causes first attachmentmember 14 to apply a first tensile force to first end portion 46 ofmedical device 12 in a first proximal direction. For example, shoulder38 of first attachment member 14 can apply the first tensile force tomedical device 12. Increasing distance 17 also causes second attachmentmember 16 to apply a second tensile force to second end portion 50 ofmedical device 12 in a second distal direction substantially oppositefrom the first direction. These tensile forces further compress themedical device 12 from an intermediate compressed outer dimension to asmaller compressed outer dimension.

Medical device 12 and delivery system 10 are then introduced into a bodylumen or cavity and advanced to a target location, for example, locationwithin or near the heart. In some embodiments, intermediate portion 48of medical device 12 remains uncovered by delivery system 10 as medicaldevice 12 is advanced to the target location.

FIG. 17 illustrates medical device 12 and delivery system 10 at a targetlocation, for example, at the aortic valve complex. At the targetlocation, first end portion 46 of medical device 12 is decoupled fromfirst attachment member 14, and second end portion 50 of medical device12 is decoupled from second attachment member 16. In some embodiments,decoupling from first attachment member 14 comprises rotating firstattachment member 14 relative to medical device 12 such that couplingmembers 52 of medical device 12 are aligned with slots 24 of firstattachment member 14, allowing first end portion 46 of medical device 12to radially expand. In some embodiments, decoupling from secondattachment member 16 comprises rotating second attachment member 16relative to medical device 12 such that coupling members 54 of medicaldevice 12 are aligned with slots 34 of second attachment member 16,allowing second end portion 50 of medical device 12 to radially expand.FIG. 18 illustrates medical device 12 decoupled from both first andsecond attachment members 14 and 16 and deployed at the target location.Then, as shown in FIGS. 19 and 20, second attachment member 16 and firstattachment member 14 can be moved relative to each other such thatsecond attachment member 16 is adjacent to first attachment member 14.At this point, delivery catheter 10 can be removed from the patientanatomy.

Although in FIG. 6 first end portion 46 is the outflow portion of avalve prosthesis, in some embodiments, first end portion 46 can be theinflow portion of a valve prosthesis, and second end portion 50 can bethe outflow portion of a valve prosthesis.

Embodiments have been described above with the aid of functionalbuilding blocks illustrating the implementation of specified functionsand relationships thereof The boundaries of these functional buildingblocks have been arbitrarily defined herein for the convenience of thedescription. Alternate boundaries can be defined so long as thespecified functions and relationships thereof are appropriatelyperformed.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingknowledge within the skill of the art, readily modify and/or adapt forvarious applications such specific embodiments, without undueexperimentation, without departing from the general concept of thepresent invention. Therefore, such adaptations and modifications areintended to be within the meaning and range of equivalents of thedisclosed embodiments, based on the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by the skilled artisan in light of the teachings andguidance.

The breadth and scope of the present invention should not be limited byany of the above-described exemplary embodiments, but should be definedonly in accordance with the following claims and their equivalents.

The claims in the instant application are different than those of theparent application or other related applications. The Applicanttherefore rescinds any disclaimer of claim scope made in the parentapplication or any predecessor application in relation to the instantapplication. The Examiner is therefore advised that any such previousdisclaimer and the cited references that it was made to avoid, may needto be revisited. Further, the Examiner is also reminded that anydisclaimer made in the instant application should not be read into oragainst the parent application.

What is claimed is:
 1. A delivery system for deploying a medical device,comprising: a first attachment member configured to selectively coupleto and radially constrain a first end portion of the medical device; anda second attachment member configured to selectively couple to andradially constrain a second end portion of the medical device, whereinthe first attachment member is configured to move relative to the secondattachment member such that the first attachment member applies a firsttensile force to the first end portion of a medical device in a firstdirection and the second attachment member applies a second tensileforce to the second end portion of a medical device in a seconddirection substantially opposite from the first direction.
 2. Thedelivery system of claim 1, wherein the first attachment membercomprises an outer surface defining a plurality of slots each configuredto receive a respective attachment portion of the first end portion ofthe medical device.
 3. The delivery system of claim 2, wherein the firstattachment member is configured to rotate such that the outer surface isradially aligned with at least a portion of attachment portions of thefirst end portion of the medical device.
 4. The delivery system of claim2, wherein the first attachment member comprises a shoulder configuredto apply the first tensile force to the first end portion of a medicaldevice.
 5. The delivery system of claim 1, wherein the second attachmentmember comprises a second outer surface defining a plurality of slotseach configured to receive a respective coupling member of the secondend portion of the medical device.
 6. The delivery system of claim 5,wherein the second attachment member is configured to rotate such thatthe second outer surface is radially aligned with at least a portion ofattachment portions of the second end portion of the medical device. 7.The delivery system of claim 5, wherein the second attachment membercomprises a shoulder configured to apply the second tensile force to thesecond end portion of the medical device.
 8. The delivery system ofclaim 5, wherein the delivery system is configured such that anintermediate portion of the medical device coupled to the deliverysystem is uncovered.
 9. A method of deploying a medical device,comprising: coupling a first end portion of the medical device to afirst attachment member of a delivery system; coupling a second endportion of the medical device to a second attachment member of thedelivery system; moving the first attachment member relative to thesecond attachment member to increase a distance between the firstattachment member and the second attachment member, wherein the movingthe first attachment member relative to the second attachment membercauses the first attachment member to apply a first tensile force to thefirst end portion of the medical device in a first direction and thesecond attachment member to apply a second tensile force to the secondend portion of the medical valve in a second direction substantiallyopposite from the first direction, whereby the medical device iscompressed to a first compressed diameter.
 10. The method of claim 9,further comprising, before the coupling the first end portion of themedical device to the first attachment member of the delivery system andthe coupling the second end portion of the medical device to the secondattachment member of the delivery system, crimping the medical device toa second compressed diameter, the second compressed diameter beinglarger than the first compressed diameter.
 11. The method of claim 10,wherein the crimping the medical device to the second compresseddiameter comprises inserting the medical device in a tubular member. 12.The method of claim 11, wherein: the coupling the first end portion ofthe medical device to the first attachment member of the delivery systemcomprises moving the tubular member in the proximal direction to coverthe first end portion of the medical device; and the coupling the secondend portion of the medical device to the second attachment member of thedelivery system comprises moving the tubular member in the distaldirection to cover the second end portion of the medical device.
 13. Themethod of claim 9, further comprising: advancing the medical devicecoupled to the first and second attachment members and to a targetlocation; and decoupling the first end portion from the first attachmentmember and decoupling the second end portion from the second attachmentmember to deploy the medical device at the target location.
 14. Themethod of claim 13, wherein an intermediate portion of the medicaldevice remains uncovered by the delivery system as the medical device isadvanced to the target location.
 15. The method of claim 13, wherein:the decoupling the first end portion from the first attachment membercomprises rotating the first attachment member such that a plurality ofslots defined by a first outer surface of the first attachment memberare aligned with a plurality of attachment portions of the first endportion of the medical device; and the decoupling the second end portionfrom the second attachment member comprises rotating the secondattachment member such that a plurality of slots defined by a secondouter surface of the second attachment member are aligned with aplurality of attachment portions of the second end portion of themedical device.
 16. A system for replacing a native heart valve of apatient, comprising: a prosthetic heart valve comprising a frame and avalve assembly coupled to the frame, the frame comprising a first endportion, an intermediate portion, and a first portion; a delivery systemfor deploying the prosthetic heart valve, the delivery systemcomprising: a first attachment member configured to selectively coupleto and radially constrain a first end portion of the prosthetic heartvalve; and a second attachment member configured to selectively coupleto and radially constrain a second end portion of the prosthetic heartvalve, wherein the first attachment member is configured to moverelative to the second attachment member such that the first attachmentmember applies a first tensile force to the first end portion of theprosthetic heart valve in a first direction and the second attachmentmember applies a second tensile force to the second end portion of theprosthetic heart valve in a second direction substantially opposite fromthe first direction.
 17. The system of claim 16, wherein: the first endportion of the prosthetic heart valve comprises a plurality ofattachment portions; the first attachment member comprises a first outersurface defining a plurality of slots each configured to receive arespective attachment portion of the plurality of attachment portions.18. The system of claim 16, wherein the tubular member comprises aninner diameter greater than an outer diameter of the second attachmentmember.